Mivacurium compared with three different doses of suxamethonium for nasotracheal intubation

Suxamethonium in the doses of 1.0, 0.5 and 0.25 mg/kg was compared with mivacurium 0.15 mg/kg in 80 patients requiring nasotracheal intubation for maxillofacial surgery in a double-blind randomized controlled trial. Anaesthesia was induced with thiopentone 5 mg/kg and alfentanil 15 micrograms/kg. Patients were randomly allocated to one of the four relaxant groups. Anaesthesia was maintained with enflurane in 70% nitrous oxide and 30% oxygen and analgesia provided with intravenous pethidine 0.5 to 1.5 mg/kg and rectal indomethacin 100mg. All patients given mivacurium or suxamethonium 1 mg/kg had acceptable intubating conditions. Significantly fewer patients given suxamethonium 0.5 mg or 0.25 mg/kg had acceptable intubating conditions (90% and 70% respectively) (P = 0.003). Poor intubating conditions requiring additional relaxation were seen in two patients given suxamethonium 0.25 mg/kg and two given 0.5 mg/kg, while no patients given suxamethonium 1.0 mg/kg or mivacurium 0.15 mg/kg required additional relaxation (P = 0.004). Only four patients had postoperative myalgia, all of whom were given suxamethonium 0.5 mg/kg or more but no significant difference between groups could be demonstrated.